Vacuum seal indicator



Aug. 9, 1938.

` am Ogg un l Patented Aeg. 9, 193s f UNITED STATES PATENToI-FICE 'VACUUM` SEAL INDICATOR Thomas S. J. Richards, Glendale, Calif., asslg-nor toDon Baxter, Inc., a corporation of Nevada Application November 6, 1935, Serial Nc.` 48,575

i 2 (Cl. 22d-M) This invention relates to a vacuum seal indicator and is particularly useful in connection with canned foods and other products as an indicator of the sterility or condition ofthe contents of the can; j

`In the manufacture and sale of foods :and other products in vacuum cans it sometimes happens that a can has a tiny opening through the sealing metal 'o-r some other part of the can and through which air enters the can. The development of bacteria, etc., inside the can results in spoiling the food. And while sometimes the bacteria develops suilicien't pressure to bulge one end of the can, it often happens that there is no visual indication which enables the purchaser or seller 'to determine the condition of the contents. Also,.it sometimes happens that the end of a can is pressed outward in the filling opera- Vtion and the bulge of a can does not mean that The invention is illustrated, in one embodimenty by the accompanying drawing, in which- Fig. 1 is a planview of a can equipped with a seal indicator embodying my invention; Fig. 2, a plan detail view of the removable seal indicator; Fig. 3, a plan detail view of a sealing n'ng employed; and Fig."4, a broken sectional view, the section being taken as indicated at line I of Fig. 1.

The invention may be employed with any type of can. In the illustration given, a circular` can A is shown having its top sealed with a cover A'. The cover or lid Af is preferable dished in its central portion I' and apertured at II. 'Ihe edge portion I2 surrounding aperture II is preferably flared up in the manner indicated more clearly in Fig; 4. A flexible sealing ring I3 of rubber or other suitable resilient material is placed about the flange or edge I2. For the purpose of providing a tight seal, I prefer to employ for the sealing ring I3` a'gumrubber or other material which has a tendency to formV an air tight connection between the parts.`

` Over the seal I3, I place the indicator cap I I. The cap It is provided centrally with a downwardly extending central neck I which passes through the aperture and has a bottom substantlally in line with the bottom wall of the depression I Il. The cap it is" also provided with an outwardly and downwardly extending flange I6, the outer or lower edge of which approaches but does n ot extend to the depressed `wall l oi lid A.

While in the specific ldescription given, I have shown a relatively small aperture in the wall I0 and a relatively small cap I4 covering the aperture,.it will be understood that the opening may be made much larger and the cap made correl0 spondingly larger; and for certain purposes, as when the can is used in connection with certain types of foods or products this may be desirable. On the other hand, it may be desirable in connection with certain productsl to greatly rel5 duce the size of the opening from that illustrated and correspondingly the size of the cap. Also, the location of the indicator device may be changed from the top of the can to any other suitable surface, a suitable recess being provided to protect the indicator from dislocation. Normally, it will be more suitable for the indicator to be located at the top of the can because the cans are placed in an upright position on the shelves, in boxes, etc.,and there is less tendency for the indicator cap to be struck.

In the operation of the device, the can may be iilled and evacuated in the usual way either by directly drawing a vacuum or by filling the can'while the contents are hot. The sealing cap 30 having been placed in position as shown more clearly in Fig. 4, an' air tight sealing is formed as the contents of the can cool and the pressure therein is reduced. The diilerentialof pressure between the atmospheric pressure on the outside of the can and the reduced pressure within the can causes the ange I6 of indicator cap I4 to be tightly pressed against the soft rubber seal I3. If the can does notpermit the inow of air into its interior, the pressure within the can 40 will remain sub-atmospheric and the indicator cap will remain in effective sealing position. If air should leak into the can and bacteria should developv therein, the pressure Within the can Would increase to the point Where the pressure Within the can was equal to or greater than the `pressure outside and under these conditions, the indicator clip Id would become loose and would fall off when the can was handled. In other words,..the sealing cap would indicate positively the condition of the contents of the can. As long as the contents were in good Icondition, the small indicator seal would `remain firmly in position. and the -'cjan could be handled just as an ordinary can. r

The recess surrounding the indicator cap provides ample protection against displacement oi' the cap. 'I'he moment, however, that the contents of the can became spoiled, the indicator cap would be pushed oil or would fall off when the can was handled.

While in the foregoing description I have set out one specific method of forming the indicator seal, it will be understood that many other methods may be employed while utilizing the invention and many changes may be made in the shape, sire and location of the indicator device without departing from the spirit of my invention. Thus, by way of example: the relative proportions of the cover A' and cap I4 may be changed so as too cause the side wall of depression I0 to extend close to the marginal edgeof cap Il, to minimize possibility of accidental dislodgment of the cap, and the top of cap il to extend substantially flush with the marginal edge portion of cover A' whereby the cap I4 would contact with the bottom of a can above it or the top of the shipping case, thus insuring the holding of the cap Il in position on the can in case the vacuum is lost and` preventing leakage and damage to other cans.

The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, but the appended claims should be construed as broadly as permissible, in view of lthe prior art.

1. A sealed package of contents susceptible of bacterial action, said package being maintained normally under vacuum, comprising a` container having one of its walls provided with alwell and 5 with an annular at ,surface portion extending about said well,' the bottom wall of said well being provided with a relatively small aperture, a sealing ring extending about said aperture, and a vacuumlndicator cap extending over said aper- 10 ture andengaging said sealing ring,y said cap being provided with a reduced neck portion extending into said aperture, but being smaller in diameter than said aperture to permit free vertical movement of the cap but substantially pre- 15 venting lateral movement thereof.

2. In combination with a vacuum container adapted for the storage of contents susceptible of bacterial action producing a spoilageV of the contents, said container havinga relatively deep well provided with a relatively small aperture in the .bottom wall thereof, said container'having an annular flange portion extending about said weil, a resilient sealing ring about said aperture, a vacuum-indicator cap-engaging said ring enclosing said aperture,'said cap and said container being provided with interlocking elements whereby vertical movement of the cap is permitted but lateral movement thereof is substantially prevented.

THOMAS S. J. RICHARDS. 

